WO2000059207A1 - Dispositif de distribution de lumiere pour systeme d'imagerie a fibre optique - Google Patents

Dispositif de distribution de lumiere pour systeme d'imagerie a fibre optique Download PDF

Info

Publication number
WO2000059207A1
WO2000059207A1 PCT/US2000/007260 US0007260W WO0059207A1 WO 2000059207 A1 WO2000059207 A1 WO 2000059207A1 US 0007260 W US0007260 W US 0007260W WO 0059207 A1 WO0059207 A1 WO 0059207A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
fibers
coupled
output ports
pixel
Prior art date
Application number
PCT/US2000/007260
Other languages
English (en)
Inventor
David J. Schoon
Original Assignee
Schoonscan, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Schoonscan, Inc. filed Critical Schoonscan, Inc.
Publication of WO2000059207A1 publication Critical patent/WO2000059207A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/12—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanning
    • H04N1/126—Arrangements for the main scanning
    • H04N1/1295—Arrangements for the main scanning using an optical guide, e.g. a fibre-optic bundle between the scanned line and the scanning elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/435—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material
    • B41J2/447—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using arrays of radiation sources
    • B41J2/46—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using arrays of radiation sources characterised by using glass fibres
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays

Definitions

  • the invention is directed to digital color printers, and methods of forming images on photosensitive media and the like. More particularly, the invention is directed to a system and method of forming multiple pixel images simultaneously via many concurrently operating beams of light.
  • Digital color printers also known as imaging systems, form visually observable images on hard copy from electronic information. Examples include xerographic printers, ink jet printers, laser, LED and CRT imagers (including black and white or color, and imaging onto silver halide media), dye sublimation and wax transfer imagers, among others.
  • xerographic printers ink jet printers
  • laser, LED and CRT imagers including black and white or color, and imaging onto silver halide media
  • dye sublimation and wax transfer imagers among others.
  • Some imaging technologies require the use of light for the creation of a latent image on a xerographic drum or on silver halide media.
  • One common way of doing this is to deflect a laser beam with a rotating polygon mirror.
  • three lasers are used, one each of (typically) red, green, and blue.
  • a commonly sought objective is to obtain high imaging speed, for example more than two square feet per minute; high resolution, for example more than 400 continuous tone pixels/inch (more than about 160 pixels/cm); and large image size, for example images from rolls of paper of 20" (approx. 50 cm) or greater width. It is also desired to minimize the size of the equipment used to produce this image.
  • speed, resolution, image size, and equipment size tend to be competing factors that must be balanced or compromised.
  • imaging technologies are in point of sale advertisements or trade show displays, many of which may need to be as large as 50" x 100" (approximately 125 cm x 250 cm) or larger. In such cases, it is desired that the text be sharp, even at close viewing distances. It is also desired that the image be created in a short time, for example less than 10 minutes. These simultaneous objectives cannot be met or approached by conventional technologies.
  • Another application is the "package printer” market which requires that photos, such as school portraits, be imaged at various sizes and with the addition of text and other graphics. To compete with other processes the imaging speed must be at least 0.25 lineal inch per second (approximately 0.6 cm per second), and text even as small as 4 point size must be clearly readable.
  • an apparatus for sequentially distributing light to multiple destinations includes a body that is rotatable about an axis, and that has a first face intersecting the axis.
  • a light guide has an input end on the first face, approximately centered about the axis, and has at least one arm leading from the input end to a respective output port positioned on a perimeter edge of the body.
  • At least one color filter is positioned at the at least one output port to filter light exiting from the at least one output port.
  • an apparatus for distributing light includes rotatable means for rotating about a first axis, light guiding means for guiding light from a first face of the rotatable means to at least one output port on a circumference of the rotatable means, and filter means for filtering light exiting from the at least one output port.
  • an apparatus for printing color images from digital data includes a light source and a light distributing device having an input port coupled to receive light from light source.
  • the light distributing device has at least two output ports provided with color filters to filter light passing therethrough from the light source.
  • the light distributing device is rotatable about an axis.
  • a plurality of fibers is optically coupled at input ends to receive light at regular intervals from the output ports as the light distributing device rotates about the axis.
  • a plurality of light valves is coupled to receive light from the plurality of fibers and is controllable in response to which particular optical fibers are presently coupled to receive light from the light distributing device.
  • FIG. 1 shows an embodiment of a light distribution device according to the present invention
  • FIG. 2 shows a detailed view of the light distribution device of FIG. 1;
  • FIG. 3 shows an arrangement of stationary fibers surrounding the light distribution device
  • FIG. 4 illustrates locations of optical fibers in an interface between stationary fibers surrounding the light distribution device and individual light valves;
  • FIG. 5 shows the orientation and electroding of the light valves relative to the first ends of the optical fibers shown in FIG. 4;
  • FIG 6 shows an enlarged portion of FIG. 5;
  • FIG. 7 shows a color digital printer in block schematic form;
  • FIG. 8 illustrates a paper path through a color digital printer
  • FIG. 9 schematically illustrates one embodiment of a light distribution device coupled through optical fibers to light valve devices.
  • FIG. 10 schematically illustrates one embodiment of control electronics to control operation of the light valves.
  • a digital color printer described in U.S. Patent 5,684,620, incorporated herein by reference, shows one particular approach to accomplishing the characteristics of speed, color quality, resolution, image size, small equipment size and reasonable cost that are required of digital color printers.
  • the printer provides for simultaneous imaging of multiple pixels. Imaging is accomplished in modules, each module containing one array of solid state (for example a PLZT or Kerr Cell type) light valves, these light valves being on a single chip. The light produced by the array of light valves is imaged by a lens onto photographic paper or other light-sensitive media. A similar image is created by other, adjacent modules, and the modules are aligned to create a continuous band of image over the entire width of the photographic paper.
  • solid state for example a PLZT or Kerr Cell type
  • the printer 1200 is illustrated in schematic form in FIG. 7.
  • the printer includes a control module, 1201, which includes a light source, and a mechanism for distributing light from the light source sequentially into stationary fiber bundles. Bundles of fibers are illustrated as conduits 1220, 1221, 1222, and 1223.
  • Each imaging module 1202, 1204, 1206, and 1208, includes a light valve chip coupled to respective conduits 1220, 1221, 1222, and 1223, and includes an associated projection lens system 1224a-1224d.
  • the projection lens system may include one or more separate lenses.
  • Each module 1202, 1204, 1206, and 1208, projects an image onto the photographic paper in respective imaging regions 1203, 1205, 1207, and 1209.
  • the imaging regions 1203, 1205, 1207, and 1209 at least abut each other, and may be aligned to slightly overlap. Only four imaging modules are shown, but any number may be used in a particular application.
  • the optical arrangement of imaging modules and photosensitive paper may be better understood by looking at the paper path, illustrated in FIG. 8.
  • Photosensitive paper 1310 is typically provided in lengths of 275 or 575 feet (approximately 84 m or 175 m) on a supply roll, 1301.
  • a dancer roller, 1303, applies tension to the paper 1310 and is free to move from side to side to maintain constant paper tension.
  • a slowly rotating capstan, 1305, controls the slow movement of the paper, typically at about 0.30"/second (approximately 0.76 cm/s) during imaging.
  • Another dancer roller, 1304, also acts to maintain constant tension on the paper 1310.
  • the paper 1310 is taken up by the takeup roll, 1302.
  • the imaging modules 1202, 1204, 1206, and 1208 project a continuous line of image across the sheet of paper 1310 at the imaging region 1306.
  • the distribution of light from the light source to the imaging modules 1208 is described with reference to FIG. 9, which shows a simplified arrangement with only a single imaging module 1208.
  • the imaging module 1208 includes a number of light valve cells 1220 for controlling the amount of light passing to the photosensitive paper 1310.
  • Light 1230 is directed from the light source 1232 to a light distribution device 1234 that distributes the light sequentially to a number of distribution fibers 1236a - 1236z.
  • Each distribution fiber 1236a - 1236z is coupled to a group of N pixel fibers 1238, where N is the number of light valve cells 1220 in the imaging module 1208.
  • Each pixel fiber 1238 within in one group is coupled to a different one of the N light valve cells 1220, therefore, there is a different light valve cell 1220 associated with each pixel fiber 1238.
  • the output ends 1240 of the pixel fibers 1238, at the opposite ends from the coupling to the distribution fibers 1236, are coupled to respective light valve cells 1220.
  • the output ends 1240 may be arranged in a specific order, for example the output ends 1240 of the pixel fibers 1238 leading from the first distribution fiber 1236a are positioned first on the light valve cell 1220, followed by the output ends 1240 of the pixel fibers 1238 leading from the second distribution fiber 1236b, and so on.
  • the last output end 1240 positioned on the light valve cell 1220 leads from the last distribution fiber 1236z.
  • each distribution fiber 1236 coupled to the distribution device 1234, each coupled to direct light to M different positions of the light valve cells 1220, where each position of the light valve cell 1220 corresponds to a printed pixel.
  • the distribution of light operates in the following manner.
  • each of the light valve cells 1220 transmits light to the distribution device 1234.
  • the distribution device 1234 distributes light into the first distribution fiber 1236a, all the first positions, marked A, on the light valve cells 1220 are illuminated.
  • each of the light valve cells 1220 is controlled to pass or block light for the pixels on the photosensitive paper corresponding to the first positions A of the light valve cells 1220.
  • the distribution device 1234 distributes light to the second distribution fiber 1236b, and so the positions B on the light valve cells 1220 are illuminated.
  • each of light valve cells 1220 is controlled to pass or block light for the pixels corresponding to the second positions B of the light valve cells 1220.
  • each of the light valve cells 1220 is controlled to pass or block light for the pixels corresponding to the last positions Z of the light valve cells 1220.
  • the structure of the light valve cells 1220 is described hereinbelow.
  • the distribution device 1234 may return to distributing light at position A to the first distribution fiber 1236a, or it may continue to distribute light at other positions, for example at positions AA through AZ, and B A through BZ, to other distribution fibers associated with other imaging modules.
  • the distribution device 1234 may be configured to distribute light to more than one distribution fiber 1236 at any one time. For example, it may be configured to simultaneously distribute light to three different distribution fibers at positions A, AA, and BA, respectively, followed by B, AB, BB, and so on until it reaches positions Z, AZ, and BZ.
  • the input ends of the pixel fibers 1238 may be bundled and positioned around the distribution device 1234 directly, without the need for the distribution fibers 1236. This avoids the optical losses encountered at the coupling between the distribution fibers 1236 and the pixel fibers 1238.
  • this approach requires the placement of a large number of pixel fibers 1238 around the distribution device 1234.
  • the pixel fibers 1238 are typically significantly smaller in diameter than the distribution fiber, and are typically fragile and easily broken. Therefore, it is convenient to protect the pixel fibers by mounting them in modules, and coupling them to the distribution device 1234 by the distribution fibers 1236.
  • each light valve cell 1220 is illuminated by multiple pixel fibers.
  • An imaging module 1208 includes a number of light valve cells 1220 on one or more light valve chips. Several imaging modules 1208 operate in parallel to ensure that the entire width of photographic media is exposed by a more or less continuous band of light. As discussed above, the timing of the control data fed to each light valve cell is made to correspond with the particular fiber or fibers being illuminated at each instant in time.
  • the color of light presented to the light valve cells 1220 changes in sequence, for example from red to green to blue and back to red, in order to print in color.
  • Each light valve cell 1220 generates not just one but many pixels across the paper. For example, if each light valve cell 1220 is coupled with 32 pixel fibers, then each light valve generates 32 pixels.
  • the number of light valves is selected to be small enough so that the requirements of the electronic control circuitry are reasonable, yet the number of light valves is high enough so that the speed of imaging is high.
  • the selection of the number of imaging modules and pixels associated with each light valve cell 1220 generally represents a compromise between system complexity and printing speed.
  • imaging modules are imaging with red light
  • other modules may be imaging with green light or with blue light.
  • some pixel fibers create images at points further ahead in the direction of paper motion while other pixel fibers create images at points further behind in that same direction. This is due to the fact that the lines of fibers are not arranged perpendicular to the direction of paper motion, but are arranged at an angle relative to the motion direction. This angular arrangement results in the use of more fibers to cover the width of the paper, resulting in a higher resolution without requiring optical fibers of smaller diameter, which are harder to work with and more susceptible to breakage.
  • the electronic data used to control the light valve chips is programmed to reflect the timing, position, and color of illumination of various pixels.
  • a clock oscillator, 1409 provides clock pulses which are counted by the transfer number counter, 1408.
  • the counter 1408 counts, for each pixel line (once for each revolution of the light distribution device described below) one count for each of the pixel fibers in the imager.
  • the fiber number count, provided by the counter 1408, serves as an address input to the memory offsets table 1407.
  • This table 1407 which may be implemented as a memory, provides a read address offset for the buffer memory 1401.
  • Memory 1401 may be large, for example, 400 megabytes in size, and contains the file to be imaged on to the paper.
  • the address offsets provided by table 1407 include compensation for the angle of each line of fibers relative to the direction of paper motion. Compensation for slight overlaps between cells and between modules may also be provided.
  • the address offsets provided by table 1407 may also account for any mechanical mismatch between modules.
  • the output of buffer memory 1401 flows into the color table memory 1402 which provides color compensation for the characteristics of the color media, and also compensates for any nonlinearities of the light valves. Such compensation typically includes general compensation,, without providing compensation for individual light valves.
  • the data output from the color table memory 1402 then flows into fiber strength memory 1403.
  • the fiber strength memory 1403 also receives as an address input the transfer number address from the counter 1408.
  • the fiber strength memory 1403 provides compensation on a fiber-by-fiber basis.
  • the compensation covers, for example, intensity variations caused by variations in fiber- to-fiber horizontal spacing that may be caused primarily by pixel fibers not being arranged exactly in a straight line with respect to their respective light valve cells, overlap between the end pixel fiber(s) in one line with the first pixel fiber(s) in the next line (or cell), and variations in the polishing of the pixel fibers.
  • the fiber strength memory 1403 ensures that at every fiber causes the same degree of exposure of the photographic paper as every other fiber.
  • the image data passes out from the fiber strength memory 1403 into each of the module buffer memories 1404.
  • Each imaging module 1202, 1204, 1206 and 1208 has its own module buffer memory 1404. Within each imaging module, the data flows from the buffer memory 1404 into a digital-to-analog (d/a) converter and high voltage driver circuit 1405 which supplies the various voltages needed by the light valves, 1406.
  • the module buffer memory 1404 typically receives data from the fiber strength memory 1403 in serial form, i.e. one pixel at a time. Changes in data transmitted to the light valves 1406 need to occur at specific points in time, and in a massively parallel format.
  • the module buffer memory 1406 therefore stores the serially received data from the fiber strength tables 1403 to permit the data to be transmitted to the light valves 1406 at the correct time and in parallel.
  • the module buffer memory 1406 receives data in a 24-bit bus, 8 bits for red, 8 for green, and 8 for blue, and delivers that data to the d/a converters and high voltage drivers, 1405, 8 bits at a time, selected for the color being imaged.
  • the color and fiber # to be selected for delivery of data to the d/a converters and voltage drivers 1405 is determined by the fiber number counter, 1410, which determines not only the distribution fiber number (for example 1 to 54) being imaged by any module at any instant, but also determines the color of imaging.
  • the fiber number counter 1410 may be a lookup table memory, and receives an address input from a phase locked loop (PLL) circuit 1411.
  • PLL phase locked loop
  • the PLL circuit 1411 synchronizes to the synchronization sensor 1412 on the light distribution device.
  • the synchronization sensor 1412 provides a sync pulse for every cycle of the light distribution device.
  • the PLL circuit 1411 divides that time interval into as many equal time intervals as are necessary to complete one full revolution of the rotating body 104. For the example discussed below with respect to Table I, this is 248 equal time intervals.
  • a digital color printer is suitable for exposing standard RA4 processable color paper (e.g., Kodak Supra II or Konica QA) for making color prints from digital information.
  • a printer may image paper having a width of 30" (approximately 76 cm), at 512 pixels/inch (approximately 200 pixels/cm) , with a lineal speed of 0.3"/second (approximately 0.76 cm/second).
  • This embodiment uses eighteen imaging modules, each imaging module imaging approximately one eighteenth of the paper width.
  • Each of the fifty four pixel fibers is sequentially illuminated in typical successive cycles of red, green, and blue light.
  • each light valve is not illuminated uniformly or completely, but selectively by, at any instant in time, one or a small number of the pixel fibers located behind each cell.
  • Each light valve cell is made, at any instant in time, optically opaque or transparent, or partly opaque, according to the magnitude of voltage applied to the light valve cell by the high voltage drivers 1405.
  • the diameter of the pixel fibers is determined by the required resolution and printing speed, and also by considerations of manufacturability. Where the pixel fibers are 0.003" (approximately 75 ⁇ m) in diameter, they are fragile and easily subject to damage. Therefore, in order to minimize the likelihood of fiber breakage during manufacturing and servicing of the imager, light is distributed within the imager first by illuminating, at the distribution device 1234, relatively large distribution fibers, typically having a diameter of approximately 0.02", or 500 ⁇ m. The light may then be transported from the distribution device 1234 to each imaging module by an associated group of distribution fibers.
  • Each 0.02" diameter distribution fiber illuminates the input ends of sixteen 0.003" (75 ⁇ m) diameter pixel fibers.
  • the repeating sequence of illumination of the fifty four distribution fibers which are presented to each imaging module are as shown in Table I. Each cycle number takes 26.25 microseconds to complete, and the overall cycle repeats indefinitely.
  • Fiber #1 means all fibers #1 in each of many, e.g., 16, light valves per module and each of 18 modules, 288 fibers in all, are illuminated.
  • the invention described herein is directed to a new method of distributing light from the light source to the distribution fibers, and of controlling the color of light illuminating the distribution fibers at any one time. It is important that, of the many pixel fibers in each array gated by a single light valve, only one or two of the pixel fibers should be brightly illuminated while the others receive little, if any, light. This assures that there is no crosstalk among the different pixels of the image. Moreover, after all of the fibers associated with one imaging module have been successively illuminated with one color, the color is changed to be successively red, green, and blue.
  • contrast ratio Another concern is contrast ratio.
  • each fiber is "off, i.e. is not illuminated, for a period of time substantially longer than it is "on", i.e. is illuminated. Therefore, any light scattered to the "off fibers is integrated by the light-sensitive media for a relatively long time.
  • a realistic requirement for contrast ratio of light presented to the fibers is of the order of 1.6 x 10 4 , which is difficult to achieve with light distribution based on a rotating mirror.
  • white light is generated by a lamp 101, for example a type ELC quartz halogen projector lamp, which contains an integral reflector (the figure shows the external surface of the reflector).
  • the white light is projected via optical paths 102 to focus on one end 103 of a light guide such as a fiber optic bundle 110.
  • a fiber optic bundle 110 includes a plurality of individual fibers, each having a diameter of 0.002" (approximately 50 ⁇ m), where the diameter of the bundle input end 103 is 0.313" (approximately 0.8 cm).
  • the output end 112 of the fiber optic bundle 110 is positioned close to the center of a rotating body 104, driven by a motor 107 to rotate about its axis at the speed which is needed to accomplish the fiber "on" times indicated above. Using the above example, this speed is 153.6 revolutions/second, or 9,216 RPM.
  • the rotating body 104 may be, for example, disk-shaped. This shape may be referred to as a "puck,” but it should be noted that other shapes may be used. It will also be appreciated that light may be focused on to the input face 116 directly, without the use of the fiber optic bundle 110.
  • a light guide 114 within the rotating body 104 has an input face 116 located at the center 108 of the face of the rotating body 104 opposing the bundle 110.
  • the input face 116 receives the light from the bundle 110.
  • the light guide 114 separates the incoming light along a number of different paths to output ports located on the outer perimeter 118 of the rotating body 104. In the particular embodiment illustrated, the light guide 114 separates the light along four different paths to output ports, of which two 105 and 106 may be seen in FIG. 1.
  • the light guide 114 may also be formed from a plurality of fiber optic strands, starting at the center 108 of the face of the rotating body, and approximately one quarter of the strands are directed to each of the four output ports arranged around the perimeter 118. Each output port may advantageously include a rectangular arrangement of fibers. In other embodiments, the light guide 114 may be coupled to any suitable number of output ports, not just four. For example, the light guide may be coupled to one, or more, output ports.
  • Each port is covered by a respective dichroic color filter 205, 206; 207 and 208.
  • filter 207 transmits blue light
  • filter 206 transmits green light.
  • the colors of the filters may be selected to optimize the exposure of the photosensitive medium, and need not necessarily be red, green or blue. Slightly more than one quarter of the fibers in the light guide 114 are used for each of the two red filtered ports 105 and 228, and slightly less than one quarter of the fibers are used for each of the green and blue filtered ports 106 and 227.
  • the number of fibers directed to each port is selected in accordance with the spectral sensitivity of the photosensitive paper upon which an image is to be printed.
  • the widths of the ports 105, 106, 227, and 228 are selected to correspond to the number of fibers which exit at each slit, which may be approximately 0.070" (around 0.175 cm).
  • the height of each port 105, 106, 227, and 228 (in the direction parallel to the rotating body's rotation axis) may be approximately .150" (0.38 cm). It will, of course, be appreciated that the ports may have non-rectangular shapes and have dimensions different from those described here for this particular example. It should also be appreciated that the variation in exposure between ports may be accomplished additionally or alternatively by variously sized apertures placed over the dichroic filters.
  • widths of the ports 105, 106, 227, and 228 are significantly less than 0.070", for example 0.035" wide, mostly only one distribution fiber is illuminated at any one time, having the effect of providing sharper images.
  • a disadvantage of this approach is, however, is that there is a lower overall light efficiency, thus necessitating that the optical source is brighter in order to obtain the same imaging speed.
  • distribution fibers positioned around the rotating body 104 to receive light from the exit ports of the rotating body 104 is illustrated in FIG. 3.
  • Various groups of distribution fibers each including a specific number of large diameter fiber optics, are placed around the rotating body 104, the fibers being spaced at regular angular intervals so as to receive bursts of light as the rotating body 104 rotates around its axis.
  • the distribution fibers may be mounted in a stationary block, or stator, (not illustrated) that contains slits to hold the fibers in position. Where there are fifty four distribution fibers for each imaging module, with 248 cycles, as described in the example above, the distribution fibers may be positioned around the rotating body 104 at regular spacings of 1.45° (1/248 of a circle).
  • the distribution fibers have a diameter of 0.02" (approximately 0.05 cm), the rotating body 104 has a diameter of 3" (7.5 cm) and the spacing between distribution fibers close to the rotating body 104 is approximately 0.038" (approximately 0.096 cm).
  • the slits in the stator that hold the fibers are 0.020" (approximately 0.05 cm) wide and 0.120" (approximately 0.3 cm) long. For clarity, only two distribution fibers are illustrated for each slit position, for example distribution fibers from the groups marked 307 and 308.
  • Each of the ports 105, 106, 227, and 228 on the rotating body 104 projects light onto the large diameter fibers.
  • the ports 105, 106, 227, and 228 are narrow, and the spacing between the circumference 118 of the rotating body 104 and the surrounding stationary fiber bundles is small, approximately only two distribution fiber positions are illuminated by each port 105, 106, 227, and 228 at each instant in time.
  • the distribution fibers are not receiving light, they "see" the surface of the perimeter 118, which is advantageously black to reduce scattered light and, therefore, provide a high contrast between light levels when the fibers are "on” and "off.
  • the eight groups of distribution fibers 301, 302, 303, 304, 305, 306, 307, and 308 illustrated in FIG. 3 support eight imaging modules.
  • the arrow 310 shows the direction of rotating body rotation.
  • a greater number of distribution fibers need to be placed at each position around the rotating body 104.
  • four distribution fibers may be located at each position for two groups of positions and five distribution fibers located per position for the remaining two groups of positions.
  • the circuitry used to control the light valve cells needs to "know" where the rotating body 104 is at each point in time.
  • One method of deducing the instantaneous position of the rotating body 104 is to project light through a small hole 130 in the rotating body.
  • a light source 132 such as a light emitting diode or a laser diode, is placed on one side of the rotating body 104 and a light detector 134, such a photodiode or phototransistor, is placed on the other side of the rotating body 104.
  • the light detector 134 detects a light signal when the hole 130 is aligned between the light source 132 and the detector 134, i.e. once every revolution of the rotating body 104. This generates a "start of scan" pulse.
  • electronic circuitry may be used to time the interval between the "start of scan” pulses and to divide this interval time into a number of equal time units, 248 time units in the current example. At the start of each such interval in time (each being 26.25 microseconds long), new data is used to control each of the various light valves according to which particular fibers are being illuminated at that time.
  • each imaging module is a light valve chip containing a number of light valve cells.
  • the light valve cells take the form of a narrow slit. Behind each of these slit-shaped light valve cells is situated a linear row of pixel fibers.
  • the pixel fibers 410 may be, for example, 75 micron (0.003") diameter, fused silica fiber optic strands, as manufactured by Polymicro Technologies, Inc., type FDP-061-067-075 A.
  • Each pixel fiber 410 has an input end 412 and an output end 414.
  • the output ends 414 are in linear groups 401 and 402 positioned behind the light valve cells.
  • the input ends 412 are in bundles 403 and 404 positioned to receive light from the distribution fibers 1236 leading from the distribution device 1234.
  • each imaging module has a group of fifty four 0.02" (500 ⁇ m) diameter distribution fibers 1236 leading from the distribution device 1234.
  • the harness 400 has sixteen linear groups 401 and 402 of output ends, corresponding to the sixteen light valve cells of the imaging module.
  • the harness 400 also has fifty-four bundles 403 and 404 of input ends, corresponding to the fifty-four distribution fibers 1236.
  • Each of the fifty four pixel fibers 410 in each linear group 401 and 402 receives light from one of the fifty-four input bundles 403 and 404. For example, if the first input bundle 403 is illuminated with red light, the first pixel fiber 410 of each of the linear groups 401 and 402 is illuminated with red light. If the second input bundle 404 is illuminated with red light, then the second pixel fiber 410 in the linear groups 401 and 402 is illuminated with red light, and so on.
  • the light valve chip 501 and associated pixel fiber output ends 414 are illustrated in FIG. 5.
  • the light valve chip 501 may be made of PLZT material, as is commonly used in solid state light valves, or may be another type of polarization modulator, including other Kerr-type modulators.
  • the light valve chip 501 includes a number of separate light valve cells 510, in this case sixteen. Light is transmitted through each light valve cell 510 from an associated pixel fiber 410.
  • the light valve cell 510 rotates the polarization of the light in response to an electric field, and is typically sandwiched between two crossed polarizers, as is described in U.S. patent no. 5,054,893.
  • Each light valve cell 510 is positioned between electrode pairs, between which an applied electric potential controls the polarization rotating properties of the cell 510.
  • each cell 510 is formed between a common electrode 504 and an individual electrode.
  • the common electrode 504 is connected to each of 16 comb-like fingers 505.
  • Individual electrodes, such as electrode 503, are connected to respective connection tabs 502.
  • the light valve chip 501 may be placed inside a cutout on a printed circuit board; conductive epoxy junctions may be made between traces on the printed circuit board and the connection tabs 502 and the common electrode 504. In this way, each light valve cell 510 may be addressed individually and separately from the other cells 510 on the chip 501.
  • any common finger electrode 505, and any individual electrode 503 generates an electric field responsive to the voltage applied between the two electrodes. Except in the cases of the end electrodes, two regions of electric field are generated, one above and one below the individual electrode 503. Only one of these regions is used as a light valve cell 510 to gate light. In the region above the individual electrode 503 and below the common finger electrode 505, all of the pixel fibers 410 are configured in a linear array.
  • each light valve array 501 having sixteen cells 510, has an active length of 1.4", so it is magnified by 1.205 times to produce an image length of 1.6875".
  • Eighteen imaging modules are positioned every 1.68" to produce a total imaging length of 30". It should be appreciated that the amount of magnification by the lens system is dependent on several factors including, but not limited to, the desired resolution, the size of the light valve chip in the imaging module and the printing speed.
  • FIG. 5 A portion of FIG. 5 is enlarged in FIG. 6 to better show the linear arrays of output ends 414 of the pixel fibers 410.
  • a light valve cell 520 is formed between individual electrode 503a and common finger electrode 505a.
  • Another light valve cell 522 is formed between another individual electrode 503b and common finger electrode 505b.
  • Pixel fibers 506 - 510 form one linear fiber array 530 in the first light valve cell 520 and pixel fibers 511 - 512 form another linear array 532 in the second light valve cell 522.
  • the direction of paper motion relative to the light valve cells 520 and 522 is illustrated by the arrow 516.
  • the fiber arrays 530 and 532 form an angle, ⁇ , relative to the direction of paper motion.
  • the angle, ⁇ , and the number of pixel fibers in each array 530 and 532 are selected so that, in the direction perpendicular to the direction of paper motion, the last fiber 510 in the first array 530, matches or slightly overlaps the position of the first fiber 511, in the second array 532. If there is overlap between the end pixel fibers of adjacent arrays, the brightness of overlapping fibers may be adjusted to compensate.
  • each light valve cell 520 and 522 is programmed to correspond to the particular pixel fiber 410 or fibers illuminated at any instant in time. If more than one pixel fiber 410, presumably adjacent, is illuminated at any instant in time, the data may correspond to the brightest pixel fiber or the average position of the illuminated pixel fibers.
  • a rotating body may be used having a different number of exit ports.
  • the ports may be provided with sequential color filters of red, green, blue, red, green, and blue. This may require a larger rotating body diameter, for example 4" rather than 3".
  • the rotating body speed needed to support a given imaging speed is one half the number of lines imaged per second on the paper, since two scans are made per revolution of the rotating body.
  • An advantage of this embodiment is that the electronic complexity, required to provide for simultaneous imaging of different colors, may be reduced. On the other hand, since the green and blue light is not used at the same time as the red light, a substantial fraction of the light is discarded in this case.
  • This embodiment illustrates the compromises that may be made between the system complexity and light use efficiency This approach may be advantageous in applications such as imaging high sensitivity film, where the amount of light is not as important, and/or the image width need not be so wide.
  • Different numbers of pixel fibers per light valve cell, and/or a different number of light valve cells per imaging module may be used. For example, the number of pixel fibers per light valve cell may be fifty, with thirty two light valve cells per light valve chip.
  • a single module with 1,600 pixels (50 x 32), may be used to expose a roll of photographic paper 4" (10 cm) wide at a resolution of 400 pixels/inch (157 pixels/cm).
  • the rate of scanning in the light distribution device primary scanner may be increased to 200 scan cycles (red, green, blue, red, of all 50 fibers each) per second.
  • the vertical imaging rate may be 0.50"/second (1.25 cm/s).
  • the number of imaging modules used across the width of the photosensitive paper may be selected depending on what particular resolution and speed are desired.
  • design aspects of the printer are dependent on the width and nature of the photosensitive medium used, such as the amount of light required to expose the medium. This may affect the printing speed.
  • the present invention is applicable to digital color printers and is believed to be particularly applicable to high speed, high resolution printers. Accordingly, the present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification. The claims are intended to cover such modifications and devices.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)

Abstract

Une imprimante couleur numérique comprend un dispositif destiné à distribuer la lumière provenant d'une source de lumière vers un certain nombre de chemins optiques différents définis par des fibres. Le dispositif de distribution de lumière comprend un corps rotatif autour d'un axe et présentant une première face coupant l'axe. Un guide de lumière présente une extrémité d'entrée sur la première face, centrée approximativement autour de l'axe, et présente au moins un bras partant de l'extrémité d'entrée vers un orifice de sortie respectif positionné sur un bord périmétrique du corps. Au moins un filtre couleur est positionné au niveau d'au moins un orifice de sortie afin de filtrer la lumière sortant au moins de l'orifice de sortie.
PCT/US2000/007260 1999-03-25 2000-03-15 Dispositif de distribution de lumiere pour systeme d'imagerie a fibre optique WO2000059207A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US27643399A 1999-03-25 1999-03-25
US09/276,433 1999-03-25

Publications (1)

Publication Number Publication Date
WO2000059207A1 true WO2000059207A1 (fr) 2000-10-05

Family

ID=23056654

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/007260 WO2000059207A1 (fr) 1999-03-25 2000-03-15 Dispositif de distribution de lumiere pour systeme d'imagerie a fibre optique

Country Status (1)

Country Link
WO (1) WO2000059207A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3325594A (en) * 1963-02-07 1967-06-13 Chicago Aerial Ind Inc Fiber optic scanning apparatus
US3922714A (en) * 1972-10-18 1975-11-25 Cit Alcatel Device for transmitting and reproducing color pictures
US4550985A (en) * 1981-06-17 1985-11-05 Mita Industrial Co., Ltd. Light deflector
EP0214504A2 (fr) * 1985-08-28 1987-03-18 Georg STUKENBROCK Dispositif d'éclairage ponctuel, en particulier pour balayage par lignes de contenus d'images planes
EP0716537A1 (fr) * 1994-12-06 1996-06-12 Noritsu Koki Co., Ltd. Appareil d'exposition
US5828483A (en) * 1993-11-23 1998-10-27 Schwartz; Nira Printing and inspection system using rotating polygon and optical fibers

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3325594A (en) * 1963-02-07 1967-06-13 Chicago Aerial Ind Inc Fiber optic scanning apparatus
US3922714A (en) * 1972-10-18 1975-11-25 Cit Alcatel Device for transmitting and reproducing color pictures
US4550985A (en) * 1981-06-17 1985-11-05 Mita Industrial Co., Ltd. Light deflector
EP0214504A2 (fr) * 1985-08-28 1987-03-18 Georg STUKENBROCK Dispositif d'éclairage ponctuel, en particulier pour balayage par lignes de contenus d'images planes
US5828483A (en) * 1993-11-23 1998-10-27 Schwartz; Nira Printing and inspection system using rotating polygon and optical fibers
EP0716537A1 (fr) * 1994-12-06 1996-06-12 Noritsu Koki Co., Ltd. Appareil d'exposition

Similar Documents

Publication Publication Date Title
US5049901A (en) Light modulator using large area light sources
US5933183A (en) Color spatial light modulator and color printer using the same
US5953103A (en) Color printer
JPH02501292A (ja) 等角度走査露出領域を有する多重化配列露出装置
EP0928696A1 (fr) Système d'imagerie à haute résolution et procédé d'imagerie utilisant ce système
EP1098216B1 (fr) Appareil pour la formation d'images du type d'exposition de lignes
US6148134A (en) Fiber mounts for fiber optic harness in a fiber optic-based imaging system
JP2001305663A (ja) 画像焼付装置およびこれを備えた写真処理装置、ならびに画像焼付方法
WO2000059207A1 (fr) Dispositif de distribution de lumiere pour systeme d'imagerie a fibre optique
JP2001305664A (ja) プリンタ
US5706075A (en) Exposure apparatus for controlling the duration of exposure operations according to compensated exposure data
JP2000194282A (ja) 映像ディスプレーシステム
JP2002122945A (ja) デジタル露光装置及びこれを備える写真処理装置
US5117245A (en) Electronic printer or scanner using a fiber optic bundle and an array light emission device
JP3700349B2 (ja) 光記録装置
JPH08201930A (ja) 露光装置
US20220244529A1 (en) Optical scanning device, image forming apparatus including optical scanning device, and optical scanning method
US6278475B1 (en) Optical writing device
JPH02162063A (ja) カラム式プリンタ
JPH02162064A (ja) カラム式光学ヘッド
JPH03138180A (ja) 記録装置
KR100243144B1 (ko) 소형칼라프린터
JP3587079B2 (ja) 焼付装置およびこれを備えた写真処理装置
JP2871493B2 (ja) 露光装置
JP3494073B2 (ja) 焼付装置および写真処理装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA IL JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase